1. Field of the Invention
The present invention relates to a ball bearing cage, to a ball bearing comprising such a cage, and to a process for assembling such a bearing.
2. Description of the Related Art
In the domain of ball bearings, so-called “rigid” bearings are known, comprising a single row of balls arranged between two so-called “inner” and outer” rings, and allowing a relative movement of rotation of the inner ring with respect to the outer ring without pivoting about an axis perpendicular to the central axis of the bearing. U.S. Pat. No. 5,015,105 describes a ring-shaped cage that may be used with such bearings.
It is also known to equip such a bearing with a cage for separating the balls, such a cage defining recesses in which the balls are received, separated from one another. Such a cage is formed by two elements assembled by fastening, riveting or clipping and requiring high-precision machinings, in order not to increase friction in the bearing too greatly. The necessity of producing such a cage in two parts results from the fact that the cage must be maintained in place in the internal space of the bearing defined between the two rings, failing which it might be driven outside this space.
The different known means for assembling the two parts of a cage most often lead to an increase in the dimensions of the joints between these two parts. For example, when rivets are used, a certain quantity of matter must be provided around each rivet, in order to reduce the risks of rupture of the cage. This leads to relatively large gaps for separation between two adjacent balls and the fact that a bearing equipped with such a cage generally cannot be subjected to an intense load.
In order to allow a maximum load capacity of a bearing, it is also known to manufacture cage-less bearings which are filled with contiguous balls, this solution leads to friction between the balls, which friction may generate considerable wear of the balls, in particular when ceramic balls are used. This solution also involves a risk of the balls escaping from the internal space of the bearing as they are not maintained in place.
As it is necessary to provide a zone for positioning the balls between the rings, the balls can be driven outwardly through this sone, when the bearing is being used.
Finally, EP-A-0 288 334 discloses producing a bearing cage from a flexible band, this cage being provided with a slot which constitutes a zone of weakness of the cage that may lead to deformations likely to release the balls, particularly in the event of axial vibrations of the bearing.
It is a particular object of the present invention to overcome these drawbacks by proposing a novel bearing cage which said cage open on a second side of said cage. avoids friction between the balls and ensures that they are held in the internal volume of a bearing without requiring complex or high-precision assembly.